RESUMO
Nematode infections induce the upregulation of mucin- and glycosylation-related genes in intestinal epithelial cells in vivo. However, the factor(s) that induce these changes in epithelial cells have not been fully elucidated. In the present study, we analysed the effects of the Th2 cytokines IL-4 and IL-13 and the excretory-secretory (ES) product of the nematode Nippostrongylus brasiliensis on the gene expression of the major mucin core peptide MUC2, the sialyltransferase ST3GalIV (Siat4c) and the sulphotransferase HS3ST1 in intestinal epithelium-derived IEC-6 cells by quantitative reverse transcription (RT)-PCR. The administration of IL-4 and IL-13 resulted in a significant upregulation of ST3GalIV and HS3ST1 gene transcription, but had no effect on MUC2, in IEC-6 cells. RT-PCR studies also demonstrated the constitutive expression of IL-13Ralpha1 and IL-4R in IEC-6 cells. On the other hand, the ES product induced upregulation of ST3GalIV, but not HS3ST1 or MUC2, while coadministration of IL-13 and the ES product induced a slight but significant upregulation of MUC2. Co-incubation of live N. brasiliensis adult worms with IEC-6 cells resulted in the upregulation of ST3GalIV and MUC2. These results suggested that HS3ST1 gene expression is strictly regulated by IL-4/IL-13, while ST3GalIV and MUC2 gene expressions are regulated by redundant mechanisms.
Assuntos
Íleo/parasitologia , Interleucina-13/fisiologia , Interleucina-4/fisiologia , Mucina-2/biossíntese , Nippostrongylus/patogenicidade , Sialiltransferases/biossíntese , Sulfotransferases/biossíntese , Animais , Antígenos de Helmintos/fisiologia , Células Epiteliais/imunologia , Células Epiteliais/parasitologia , Perfilação da Expressão Gênica , Íleo/imunologia , Masculino , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , beta-Galactosídeo alfa-2,3-SialiltransferaseRESUMO
Infections with helminthic parasites occasionally induce pulmonary diseases with possible involvement of immunological mechanisms. In rats infected with the nematode Nippostrongylus brasiliensis, pulmonary granulomatous lesions develop and persist after the larvae have migrated through the lungs. To determine the pathogenesis of this lesion, we examined cytokine gene expression in the lungs using RT-PCR and in situ hybridization. Two weeks after infection, when fully developed lesions appeared, levels of IL-3 and of type2 cytokines IL-4, IL-5, IL-6 and IL-13 gene expression were markedly enhanced in whole lung homogenates. Those of IL-2 and IFN-gamma were also slightly increased 2 weeks postinfection. IL-12 mRNA level did not change after 2 weeks but was slightly increased after 4 weeks. Levels of IL-10 and proinflammatory cytokine TNF gene expression did not show significant changes, although a slight increase was observed in IL-1beta message after 2 weeks. In situ hybridization studies showed that lung granulomatous lesions were composed mainly of lymphoid cells expressing IL-3, IL-4 and IL-13 mRNA, but not IFN-gamma mRNA. IL-5 mRNA-expressing cells were fewer in number than these cells. RMCP II immunohistochemistry revealed that mast cells increased in number in the lung granulomas. From these results, it was concluded that the nematode infection-associated lung granuloma was a type 2 lesion.
Assuntos
Citocinas/genética , Pneumopatias Parasitárias/imunologia , Pulmão/imunologia , Nippostrongylus/imunologia , Infecções por Strongylida/imunologia , Células Th2/imunologia , Animais , Modelos Animais de Doenças , Expressão Gênica , Pulmão/patologia , Pneumopatias Parasitárias/genética , Pneumopatias Parasitárias/patologia , Masculino , RNA Mensageiro/metabolismo , Ratos , Ratos Endogâmicos BN , Infecções por Strongylida/genética , Infecções por Strongylida/patologiaRESUMO
Autoinfective strongyloidiasis is potentially fatal, yet the majority of infected individuals harbour asymptomatic and chronic infections. The role of humoral responses in modulating autoinfection was assessed by examining antibody isotype responses to filariform larval antigens amongst chronically infected ex-Far East Prisoners of War (exFEPOWs) with longstanding (> 30 years) infection. Serum immunoglobulin (Ig)G1, IgG4, IgE and IgA responses to whole Strongyloides stercoralis L3 extracts and their constituent antigenic components were characterized by ELISA and quantitative immunoblotting. Comparison of two groups of S. stercoralis infected exFEPOWs with and without detectable larvae in stool demonstrated novel trends. Significantly enhanced recognition of six immunodominant antigenic components by IgA was associated with undetectable larval output, as was enhanced IgE recognition of several components. Additionally, IgE and IgG4 exhibited parallel antigen recognition patterns. These findings are consistent with roles for IgA in modulating larval output, for IgE in regulating autoinfection, and for IgG4 in blocking IgE-mediated responses in human strongyloidiasis.
Assuntos
Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Citocinas/genética , Nippostrongylus , Infecções por Strongylida/imunologia , Actinas/genética , Animais , Linfonodos/metabolismo , Masculino , Mesentério , RNA Mensageiro/análise , Ratos , Ratos Endogâmicos F344RESUMO
It has been reported that infection with Nippostrongylus brasiliensis induces villus atrophy with various histological alterations. In N. brasiliensis-infected rats, villus length in the jejunum was reduced significantly at day 10 p.i., when serum levels of rat mast cell protease (RMCP) II had increased significantly. To determine whether the villus atrophy is associated with enhancement of apoptosis, apoptotic nuclei were labelled using the nick end-labelling method. Numbers of labelled cells were markedly increased in the villus epithelium at 7-10 days p.i., while the numbers returned to normal 14 days p.i. when worms were rejected from the intestine and villus length became normal. Examination of the expression of the adhesion molecule E-cadherin showed granular immunoreactivity in the cytoplasm of atrophic villus epithelium with loss of normal localization to epithelial cell borders. In mast cell-deficient Ws/Ws rats, villus length was reduced as significantly as in +/+ counterparts at day 10 p.i. with marked increases in the numbers of apoptotic cells. These results suggested that villus atrophy was closely associated with enhanced apoptosis and loss of adhesion in epithelial cells. Mast cell activation appears not to be involved in these alterations.
Assuntos
Apoptose , Mucosa Intestinal/patologia , Intestino Delgado/patologia , Nippostrongylus/parasitologia , Infecções por Strongylida/patologia , Animais , Atrofia , Caderinas/isolamento & purificação , Adesão Celular , Quimases , Grânulos Citoplasmáticos , Mucosa Intestinal/parasitologia , Intestino Delgado/parasitologia , Masculino , Mastócitos/enzimologia , Antígeno Nuclear de Célula em Proliferação/isolamento & purificação , Proteínas Proto-Oncogênicas c-kit/genética , Ratos , Ratos Mutantes , Serina Endopeptidases/sangue , Infecções por Strongylida/parasitologiaRESUMO
Ws/Ws rats are deficient in both mucosal- and connective tissue-type mast cells. To study the role of mast cells in active anaphylaxis, changes in vascular permeability in the trachea upon intravenous antigen challenge with Evans blue dye were examined in Ws/Ws, heterogenic Ws/+, and normal +/ + rats sensitized with the nematode Nippostrongylus brasiliensis. Antigen challenge resulted in fatal anaphylactic shock in some +/+ and Ws/+ rats, but not in Ws/Ws rats. Marked dye leakage developed within 30 min in the trachea of +/+ and Ws/+ rats, while Ws/Ws rats showed no substantial increases in the levels of vascular permeability. Ex vivo stimulation of sensitized lung fragments from +/+ animals with specific antigen induced significant releases of histamine and leukotriene (LT) C4, while sensitized Ws/Ws rat-lung fragments did not. In Ws/Ws rats, levels of nematode-specific IgE, IgG1 and IgG2a antibodies as well as levels of lung eosinophilia were not significantly different from those in +/+ rats. These results show that mast cell-deficient Ws/Ws rats fail to develop active anaphylaxis, and this is mediated probably by the lack of mast cell-derived mediators required for initiation of the reaction.
Assuntos
Anafilaxia/imunologia , Anafilaxia/parasitologia , Pulmão/imunologia , Pulmão/parasitologia , Mastócitos/imunologia , Mastócitos/parasitologia , Nippostrongylus/imunologia , Animais , Anticorpos Anti-Helmínticos/biossíntese , Anticorpos Anti-Helmínticos/sangue , Antígenos de Helmintos/imunologia , Permeabilidade Capilar , Contagem de Células , Liberação de Histamina , Imunização , Leucotrieno C4/metabolismo , Pulmão/metabolismo , Pulmão/patologia , Mastócitos/patologia , Ratos , Ratos Mutantes , Infecções por Strongylida/imunologia , Infecções por Strongylida/metabolismo , Infecções por Strongylida/patologia , Traqueia/irrigação sanguíneaRESUMO
The effects of lactic dehydrogenase virus (LDV) infection on the protective immune responses to the nematode Nippostrongylus brasiliensis were studied. Mice with chronic LDV infection showed significantly higher levels of parasite egg production than non-LDV-infected (control) mice after N. brasiliensis infection. Concurrent LDV infection also suppressed peripheral blood eosinophilia and the lung mastocytosis induced by this nematode. LDV infection showed higher expression levels of the interferon-gamma (IFN-gamma) mRNA in lymph nodes compared with control mice before N. brasiliensis infection. In addition, the IgG2a production in LDV-infected mice was higher than that in control mice before and after N. brasiliensis infection. These results suggest that LDV infection modulates protective immune responses against N. brasiliensis infection by the activation of T-helper type 1 cells.
Assuntos
Infecções por Arterivirus/imunologia , Vírus Elevador do Lactato Desidrogenase , Nippostrongylus , Infecções por Strongylida/imunologia , Animais , Infecções por Arterivirus/parasitologia , Doença Crônica , Eosinófilos/imunologia , Imunoglobulina E/sangue , Imunoglobulina G/sangue , Interferon gama/biossíntese , Jejuno/imunologia , Contagem de Leucócitos , Pulmão/imunologia , Linfonodos/imunologia , Masculino , Mastócitos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Contagem de Ovos de Parasitas , RNA Mensageiro/metabolismo , Infecções por Strongylida/parasitologiaRESUMO
Development of basophilic leukocytes was studied in the Mongolian gerbil, Meriones unguiculatus, after infection with the nematode Nippostrongylus brasiliensis. After infection, peripheral blood basophilia developed and peaked at 2 weeks. In bone marrow sections, numbers of alcian blue+/safranine- basophilic cells were increased. These cells did not bind berberine sulfate and were clearly distinguishable from the bone marrow-resident mast cells, safranine+ and berberine sulfate+. Alcian blue+/safranine- cells were identified by electron microscopy as basophilic myelocytes in various stages of maturation. In the early period of infection, these cells had round-to-oval granules with a homogenous electron-dense matrix, a well-developed Golgi apparatus and rough endoplasmic reticulum, and a nonsegmented nucleus. By enzyme cytochemical analysis, intense peroxidase activity was demonstrated in all of the specific granules as well as in the rough endoplasmic reticulum and Golgi apparatus. Two weeks after infection, the number of bone marrow basophilic cells further increased, forming distinct clusters or islands composed of up to 100 cells each. On electron micrographs, the basophilic cells in these clusters appeared to be late-stage basophilic myelocytes, ie, having an increased number of granules, a less-conspicuous Golgi apparatus and rough endoplasmic reticulum, a horseshoe-shaped-to-lobulated nucleus, and reduced peroxidase activity. Eosinophils and mast cells were rarely found in the basophilic cell clusters. Four weeks after infection, the clusters had disappeared. These results show that gerbil basophilic myelocytes tend to form cell clusters in the bone marrow during their active proliferation. The comparative paucity of other cell lineages in basophilic cell clusters suggests that basophilia is generated from differentiation/proliferation of precommitted basophil progenitors independently from cells of other lineages.
Assuntos
Basófilos/patologia , Medula Óssea/patologia , Células-Tronco Hematopoéticas/patologia , Células-Tronco Hematopoéticas/fisiologia , Nippostrongylus , Infecções por Strongylida/patologia , Infecções por Strongylida/fisiopatologia , Azul Alciano , Animais , Basófilos/fisiologia , Basófilos/ultraestrutura , Medula Óssea/fisiopatologia , Corantes , Grânulos Citoplasmáticos/patologia , Grânulos Citoplasmáticos/ultraestrutura , Gerbillinae , Contagem de Leucócitos , Microscopia Eletrônica , Fenazinas , Infecções por Strongylida/sangue , Fatores de TempoRESUMO
Certain nematode infections induce eosinophil infiltration and granulomatous responses in the lungs. To examine the role of mast cells in the development of lung lesions, normal +/+ and genetically mast cell-deficient Ws/Ws rats were infected with the nematode Nippostrongylus brasiliensis. In +/+ rats, numbers of eosinophils in bronchoalveolar lavage fluid (BALF) increased significantly 3-7 days after infection, and granulomatous responses composed of histiocytes/ macrophages and multinucleate giant cells were triggered in the lungs 3-14 days after infection. Challenge infection, which was carried out on day 28 after primary infection, induced much higher levels of granulomatous response than after primary infection, suggesting that the response is mediated at least in part by an immunological mechanism. In Ws/Ws rats, both the eosinophil percentage in BALF and the size of the granulomas in the lungs were significantly smaller than in +/+ rats after primary as well as after challenge infection. The amount of rat mast cell protease (RMCP) II in +/+ rat BALF was increased 1 day after primary infection and more significantly after challenge infection, suggesting that lung mucosal mast cells were activated more markedly after the challenge infection. In Ws/Ws rats, RMCP II was undetectable throughout the observation period. The time course of nematode migration in the lungs did not differ in +/+ and Ws/Ws rats. These results suggest that mast cell activation might be relevant to eosinophil infiltration and granulomatous response in the lungs, although the responses do not affect lung migration of the nematode.
Assuntos
Granuloma/imunologia , Tolerância Imunológica/genética , Enteropatias Parasitárias/imunologia , Pulmão/imunologia , Mastócitos/imunologia , Nippostrongylus/imunologia , Infecções por Strongylida/imunologia , Animais , Granuloma/genética , Granuloma/patologia , Enteropatias Parasitárias/genética , Enteropatias Parasitárias/patologia , Pulmão/patologia , Ratos , Ratos Mutantes , Infecções por Strongylida/genética , Infecções por Strongylida/patologiaRESUMO
Worm expulsion of, and IgE and interferon (IFN)-gamma responses to, Nippostrongylus brasiliensis were studied in 2 rat strains, Brown Norway (BN) and Fischer (F)-344. BN rats expelled the majority of worms by day 14 post-infection (p.i.) with approximately 6% of worms surviving for at least 3 weeks. In F-344 rats, worm expulsion was delayed by 2 days relative to that in BN, while the numbers of residual worms were significantly fewer than in BN, suggesting that different immune mechanisms are involved in early and late phases of immunity. Total serum IgE, as well as in vitro IgE production by mesenteric lymph node (MLN) cells, was increased 2 weeks p.i., the levels being markedly higher in BN than in F-344 rats. Serum rat mast cell protease II was also increased more significantly in BN than in F-344 rats. In contrast, production of IgG2a and IFN-gamma by MLN and spleen cells was found to be higher in F-344 than in BN rats. These results indicate that the early worm expulsion is correlated with the host IgE and mast cell responsiveness, whereas the persistence of infection in the late period may be controlled by different immune mechanisms.
Assuntos
Anticorpos Anti-Helmínticos/sangue , Interferon gama/biossíntese , Nippostrongylus , Infecções por Strongylida/imunologia , Animais , Anticorpos Anti-Helmínticos/biossíntese , Formação de Anticorpos , Quimases , Ensaio de Imunoadsorção Enzimática , Fezes/microbiologia , Imunoglobulina E/biossíntese , Imunoglobulina E/sangue , Imunoglobulina G/biossíntese , Imunoglobulina G/sangue , Imunoglobulina G/classificação , Intestino Delgado/parasitologia , Masculino , Nippostrongylus/imunologia , Nippostrongylus/isolamento & purificação , Contagem de Ovos de Parasitas , Anafilaxia Cutânea Passiva , Ratos , Ratos Endogâmicos BN , Ratos Endogâmicos F344 , Serina Endopeptidases/análise , Fatores de TempoRESUMO
The number of goblet cells in the small intestines of C3H/HeN mice increased rapidly following their infection with about 500 third-stage larvae (L3) of the intestinal nematode Nippostrongylus brasiliensis. The number of goblet cells reached its peak on day 9 postinfection (p.i.). Worm burdens in the hosts' small intestines were determined following a challenge infection with encysted metacercariae of the intestinal trematodes Echinostoma trivolvis or E. caproni on days 8 and 16 after primary infections with N. brasiliensis. All metacercariae of E. trivolvis or E. caproni used to challenge the hosts on day 8 p.i. were expelled. Considerable numbers of E. trivolvis (48.6%) and E. caproni (67.1%) remained in the intestines of hosts challenged with these echinostomes on day 16 p.i. All the controls used for E. trivolvis and E. caproni infections without primary infections with N. brasiliensis showed recovery rates greater than 70%. An enzyme-linked immunosorbent assay (ELISA) showed that the IgM titer rose remarkably and plateaued on day 11 p.i. No marked rise in the IgG or IgA titer occurred during the experiment. These results indicate that mucins increased by hyperplastic goblet cells associated with primary infections with N. brasiliensis are responsible for a rapid expulsion of the worms of the challenge infection with E. trivolvis or E. caproni from the mouse host.